How Many Hours??

[Bill Burgette]

I'm getting ready to take some vacation and go boat buying/looking. I've read this forum at least twice a day for the last few months to increase my knowledge. In order to help me get my ducks in a row:

I was wondering how many hours is too many on a diesel? I realize that everyone doesn't have the same preventive maintenance and care that many of you do so let's just assume they were reasonably attentive and did most things when they were supposed to.

How many hours should I be concerned with? Is the longevity of most engines similar to each other? On land, an engine running at 50 mph for 3000 hours would have put up 150,000 miles on the odometer. Would that equate to a similar wear pattern for a marine diesel. How many hours are on your diesel and how's it run? Sorry for all the nosy questions but I've gotta know.
Thanks Sailors and Sailorettes ---Bill---

[amarinesurveyor]

Bill,
I think the 50 mph in a car analogy is a good one except that the boat engine is more heavily loaded than a car engine loafing along at 50 mph. The answer is: It all depends on how the boat engine is run and maintained. Most naturally aspirated (non-turbo) diesels are capable of running 5,000 to 10,000 hours before being overhauled. Regular oil changes and fuel filter changes are key to long engine life.
Brian

[Talbot]

When I fitted my diesel outboard, they were expecting 10000 hours at least. In the event, I did not use it very frequently per year (prefering to sail for some reason), and although I am sure this was a reasonable estimate for the engine, the pivot tube and transom clamp needed attention much earlier.

[cdennyb]

assuming 8 mph (I know it isnt knots/hr but bear with me.) for 5000 hrs, that's only 40,000 miles of basically good rpm's. Remember how the taxi cabs in new york got 500,000 miles from their cars? It was mainly due to the fact they never shut them off. But I know you only run a diesel in a S/V for a limited amount of time but my point is that it's run at a good rpm for wear, tear... and they are up to operating temp quickly and maintained at that temp during the loaded useage.

Make sense?
I would do an oil sample and send it off for analysis and see if there's anything excessive in there as well as water, antifreeze, iron, aluminum, bronze, etc.
I wouldn't hesitate at a engine with 5000 hrs. on it.

[maxingout]

I have 4500 hours on each of my 3GM30F Yanmar diesel engines, and they are stil going strong after more than 14 years of use.

[perchance]

Automotive and marine diesels are apples and oranges. Automotive diesels are expected to spend their working life running through the full spectrum of their rpm range whereas marine diesels like tractors and other industrial diesels are set at one ideal rpm and run for hours putting out constant horse power and if properly maintained will virtually run for ever. Notice I said virtually.

[Dave the Canuck]

I asked this question of the mechanic who looks after my boat and who's done this for MANY years. He says a minimum of 5000 hours pre major work for a decently maintained marine diesel.

[Bill Burgette]

Thanks guys, that's just what I was looking for. A "decently" maintained 1500 hour engine is what I was inquiring about.

[roverhi]

I talked with one mechanic at a major yard on SF Bay. He feels that older low hour engines are more prone to failure than high hour engines. It is harder on an engine to sit for long periods with only short time use in between than to be run regularly for longer periods.

Aloha
Peter O.
Pearson 35

[Celestialsailor]

Yanmar=10,000 hours
Isuzu=10,000 hours
Perkins=10,000 hours
Volvo 2000 series=100 hours

[David M]

One mechanic at a boat yard once told me that yacht engines typically corrode out before they wear out. They typically get very little use and maintenance. After spending 20 years sitting at the dock 98% of their lives, they either need to be rebuilt or replaced from corrosion.

[Chief Engineer]

I worked with a Fairbanks-Morse Mechanic...he showed me a picture of a Fairbanks-Morse engine in the Carribean in a generating plant that has been running non-stop for 7 years.........they change the oil while the engine is running.